April 20, 2009

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A picture – even a fleeting glimpse – can be worth a thousand words. As soon as you spot a bird, your eyes take in the overall pattern of light and dark. And if the light allows, you’ll probably glimpse the main colors as well. This is all you need to start your identification.

Use these quick glimpses to build a hunch about what your mystery bird is, even if you just saw it flash across a path and vanish into the underbrush. Then, if the bird is kind enough to hop back into view, you’ll know what else to look for to settle the identification.

Imagine a walk through a western forest, for example: A small, bright-yellow bird flits into the understory. Yellow immediately suggests a warbler (or the larger Western Tanager). Did you pick up a hint of grayness to the head? Or perhaps some glossy black? Just noticing that much can put you on track to identifying either a MacGillivray’s Warbler or a Wilson’s Warbler.

Some birds have very fine differences that take practice even to see at all. But don’t start looking for those details until you’ve used overall patterns to let the bird remind you what it is. Read on for a few tips about noticing patches of light and dark, the boldness of a bird’s markings, and making the most of outrageous colors.

Light and Dark

When you’re trying to make an ID, focus on overall color pattern instead of matching every detail to the pictures in your field guide. Remember that birds molt and their feathers wear. Their appearance can vary if the bird is old or young, or by how well it had been eating last time it molted. And of course, the light the bird is sitting in can have a huge effect on the colors you see.

At a distance and in very quick sightings, colors fade and all that’s left are light and dark. It helps to familiarize yourself with common patterns. For example, American White Pelicans are large white birds with black trailing edges to their wings. Snow Geese are similarly shaped and colored, but the black in their wings is confined to the wingtips.

Male Harlequin Ducks are so strongly patterned that it's very difficult to mistake them for anything else. Photo by Jim Paris via Birdshare.

Even with a brief view of a flying bird, color patterns can lead you to an ID. Northern Harriers always show this conspicuous white rump patch. Photo by Bob Powell via Birdshare.

Sparrows are some of the toughest birds to identify in North America. But notice that warm rufous patch on the shoulder and you know you have a Vesper Sparrow. Photo by Tripp Davenport via Birdshare.

Patterns are really important for ducks, because you're often looking at them from a long way off. Ring-necked Ducks are dark at both ends and on the back, but pale in the middle. Photo by Gerry Dewaghe via Birdshare.

Northern Shovelers have the opposite pattern from Ring-necked Ducks. Their bodies are dark in the middle with white patches at both ends – a pattern that remains visible even when you're too far away to see any color. Photo by ashockenberry via Birdshare.

Just like with ducks, you're often looking at raptors from a long way off. The pale flight feathers and base of tail and the dark "wrist" patches, belly patch, and tip of tail combine for a pattern unique to the Rough-legged Hawk. Photo by Bill Corwin via Birdshare.

Many birds are white with black wingtips. In Snow Geese, just the outer half of the wing is black. Photo by Michael Hogan via Birdshare.

Ring-necked Ducks and scaup are dark ducks with a pale patch on the side; Northern Shovelers are the opposite: light-bodied ducks with a dark patch on the side. Many birds are dark above and pale below – a widespread pattern in the animal world that helps avoid notice by predators. By reversing this pattern, male Bobolinks, with their dark underparts and light backs, look conspicuous even from all the way across a field.

Other birds seem to be trying to call attention to themselves by wearing bright patches of color in prominent places. Male Red-winged Blackbirds use their vivid shoulder patches to intimidate their rivals (notice how they cover up the patches when sneaking around off their territory). American Redstarts flick bright orange patches in their wings and tail, perhaps to scare insects out of their hiding places.

Many birds, including Dark-eyed Juncos, Spotted and Eastern towhees, American Robins, and several hummingbirds, flash white in the tail when they fly, possibly as a way of confusing predators. White flashes in the wings are common, too: look for them in Northern Mockingbirds, Acorn, Golden-fronted, and Red-bellied woodpeckers, Common and Lesser nighthawks, and Phainopeplas.

Bold and Faint

There are some confusing bird species that sit side by side in your field guide, wearing what seems like the exact same markings and defying you to identify them. Experienced birders can find clues to these tricky identifications by noticing how boldly or finely patterned their bird is. These differences can take a trained eye to detect, but the good news is that there’s a great trial case right outside at your backyard feeder.

House Finches are common backyard birds across most of North America. Much of the continent also gets visits from the very similar Purple Finch. Males of the two species are red on the head and chest and brown and streaky elsewhere. The females are both brown and streaky. So how do you tell them apart? Look at how strongly they’re marked.

Female Purple Finches have similar size, shape, and streakiness as female House Finches. But the streaks are a much more crisply defined brown on white. Overall, the patterns of these two species are quite distinct. Photo by Gary Lee/PFW.

Female House Finches are covered in blurry, grayish brown streaks. There's little contrast between the streaks and the background color. Photo by Raymond Belhumeur/PFW.

Young Cooper's and Sharp-shinned hawks are extremely similar. In Cooper's Hawks, the brown streaking on the underparts tends to be narrower and more delicate. Photo by Ed Schneider via Birdshare.

In comparison, the streaking on young Sharp-shinned Hawks tends to be broader and blurrier. Photo by Lana Thompson via Birdshare.

The common and widespread Song Sparrow is variable across its range, but usually has a russet- and gray-striped head and bold streaks on the chest and flanks. Overall, the markings are fairly coarse. Photo by Kevin Bolton via Birdshare.

Lincoln's Sparrows look quite similar to Song Sparrows - but notice the crisper markings. The breast streaks are finer; the facial stripes more crisply defined. Photo by nieke's nature via Birdshare.

Male House Finches tend to be boldly streaked down the flanks, whereas male Purple Finches are much paler and more diffusely streaked. Even the red is more distinct, and more confined to the head and breast, in a male House Finch. Male Purple Finches look washed all over, even on the back, in a paler raspberry red.

The all-brown females of these two species are an even better way to build your skills. The streaks on female House Finches are indistinct, brown on brown, with little actual white showing through. If a female Purple Finch lands next to it, she’ll stand out with crisply defined brown streaks against a white background, particularly on the head.

Once you’ve had some practice, these small differences can be very useful. Similar degrees in marking can be seen between the coarsely marked Song Sparrow and finely painted Lincoln’s Sparrow, and between immature Sharp-shinned and Cooper’s Hawks.

Outrageous Color

Some birds flash by in such splendid color that they can only be one of a very few things.

These are some of the gratuitous pleasures of being a bird watcher: a blazing-orange male oriole; a scarlet cardinal or tanager; a Mountain Bluebird as pale as a winter sky. All-out assaults on your eyes like the Painted Bunting and Green Jay, or a Gulf Coast oak tree dripping with spring warblers.

Colors like these are high on the list of reasons many of us started bird watching – you probably don’t need a tip from us to notice them. But we do encourage you to use those colors for a near-instant identification. Then sit back and enjoy the view.